William de Valence, 1st Earl of Pembroke

William de Valence, 1st Earl of Pembroke (1225-18 May 1296) was a French nobleman and knight who served King Henry III of England.

Biography
William de Valence was the fourth son of Henry X of Lusignan and Isabella of Angouleme. In 1247, he accepted an invitation from King Henry III of England to come to England as France overran his family's lands in Poitou. He married Joan de Munchensi, the granddaughter of William Marshal, 1st Earl of Pembroke, and he inherited the Earldom of Pembroke and the lordship of Wexford in Ireland. During the Second Barons' War, the Earl of Pembroke sided with King Henry against the rebellious barons, and he was forced to flee to France following the Battle of Lewes. In 1265, however, he took part in the capture of Gloucester and the Battle of Evesham, and he accompanied Prince Edward to Palestine on the Ninth Crusade. He also took part in England's campaigns against the Welsh rulers Llywelyn the Last and Dafydd ap Gruffudd. He died in Bayonne, France in 1296.